Comprehensive Control System for Parallelable 60 Hz-2MVA Harbor AC/AC Converters

A high-performance parallelable 2 MVA, 50/60 Hz ac/ac frequency converter for harbor applications was designed and built. A specific comprehensive digital control system was set up, in order to obtain optimal current sharing among two or more parallel power converters. The control, based on a master-slave strategy, also guarantees good system availability in case of faults, even when the master is affected, by switching off the faulty converter and assuring continuous system operation under power derating. The control system was designed using MATLAB/ Simulink/PLECS tools, and tested with reduced-scale prototypes. After fine tuning a good agreement between prototype measurements and simulations was obtained. The full-size system, composed of two 2 MVA converters, was then fabricated and tested, demonstrating performances compliant with the requirements and aligned with simulations and measurements performed on the prototypes.